1. Field of the Invention
Embodiments relate generally to photodetector structures and photodetector devices, such as but not limited to photodiode structures and photodiode devices, within photonic circuits. More particularly, embodiments relate to integration of photodetector structures and photodetector devices, such as but not limited to photodiode structures and photodiode devices, with additional structures and additional devices within photonic circuits.
2. Description of the Related Art
The monocrystalline silicon-on-insulator (SOI) platform enables signal modulation and low-loss waveguiding in the telecommunication wavelength signal bands centered at λ=1.3 μm and 1.55 μm. These modulation and waveguiding functions can be implemented due to a 1.12 eV bandgap of bulk monocrystalline Si, which only produces significant linear absorption for λ<1.1 μm. To add infrared (IR) telecommunication wavelength photodetection capabilities to silicon photonic circuits, other non-silicon materials typically must be added. Compound semiconductors such as indium phosphide-based materials may be heterogeneously integrated with silicon photonic circuits, but more-desirable monolithic integration is limited due to material restrictions in complementary metal-oxide semiconductor (CMOS) processing environments. In contrast, germanium may be monolithically integrated as an absorbing material in CMOS processing environments. However, epitaxial growth of Ge-on-Si requires complex processing steps to manage a 4% lattice mismatch between a germanium crystal structure and a silicon crystal structure.
Given a continued interest in IR telecommunication wavelength signal photodetection within silicon photonic circuits, desirable are additional silicon photonic structures, silicon photonic devices and related methods that provide for IR telecommunication wavelength photodetection while providing for ready fabrication while using conventional silicon photonic structure fabrication processes and conventional silicon photonic structure fabrication methodology.